Lagrange Inversion Counts 35241-Avoiding Permutations

David Callan
Department of Statistics
University of Wisconsin-Madison
1300 University Ave
Madison, WI 53706-1532
USA

Abstract:

In a previous paper, we showed that 35241-avoiding permutations are counted by
the unique sequence that starts with a 1 and shifts left under the self-composition
transform. The proof uses a complicated bijection. Here we give a much simpler proof
based on Lagrange inversion.